Suppressor cells which function via DNA at the cell surface (cell surface DNA) have been identified in AKR leukemia. Cell surface DNA ion cells can be enriched on immunoabsorbant columns. We have been unable to identify the DNA at the cell surface after this enrichment procedure. We plan to clone the cell surface DNA ion cells using growth factors from ConA stimulated spleens. After cloning membranes will be prepared and DNA analyzed by polyacrilimide gel electrophoresis.